The diseased area such as a tumor of biological tissues is diagnosed, since the tissues are harder than the other normal tissues, by constructing an elastic image of the cross-section of a living body including the target region based on the elastic information wherein the elasticity of the biological tissues are measured by an ultrasonic diagnostic apparatus or magnetic resonance imaging apparatus. The relevant prior art is disclosed in Patent Documents 1 and 2.
As for an elastic image, for example, for an ultrasonic diagnostic apparatus, an image such as a displacement distribution image constructed by obtaining displacement of the biological tissues while the pressure is added to the target region, strain image obtained based on the previously acquired displacement, and an elasticity modulus image obtained based on the strain and stress of the respective regions of the biological tissues are generally known. These elastic images are suitable for screening tests since they can be acquired in real time. Such elastic images are generally colored by color mapping in accordance with the elastic information.    Patent Document 1: JP-A-H5-317313    Patent Document 2: JP-A-2000-60853